Automatic motor-driven leveler for loading ramp



April 16, 1963 C. L. LODJ|C ETAL AUTOMATIC MOTOR-DRIVEN LEVELER FORLOADING RAMP Filed Aug. 5, 1960 /NVEA/7'0R$ CA R1. L. LODJ/C,

ROBERT D. L/CH 7'/ 5y THE/l? ATTORNEY-S HARE/8. K/ECH, Ausszu. &KER/v3,086,152 AUTOMATIC MGTOR-DRIVEN LEVELER FGR LOADING RAMP Carl Lodjicand Robert D. Lichti, Long Beach, Calif.,

assignors by mesne assignments, to Stanray Corporatron, Chicago, ill., acorporation of Delaware Filed Aug. 5, 1961 Ser. No. 47,737 Claims. (Cl.SIS-32) The present invention relates in general to an apparatusresponsive to relative movement of two relatively movable structures formaintaining such structures in the same relative positions. Expresseddifferently, the present invention relates to an apparatus which causesone of a pair of relatively movable structures to follow the other inresponse to movement of the latter so as to maintain the two structuresin the same relative positions.

In general, the invention contemplates an apparatus which includesreversible motor means for moving one of the structures bidirectionallyand a control means responsive to relative movement of the twostructures for operating the reversible motor means in directions tomaintain the two structures in .the same relative positions. In thepreferred embodiment of the invention, the control means is carried bythe following structure, i.e., the structure to which the reversiblemotor means is connected, and is engageable with the other structure.

A primary object of the invention is to provide a control means on thefollowing structure which includes a pivoted sensing member adapted tofrictionally and rollably engage the adjacent structure to sensemovement of the adjacent structure relative to the following structure.Such frictional, rolling engagement between the sensing member and theadjacent structure reduces to an absolute minimum the possibility ofdamage to the adjacent structure by the sensing member, which isparticularly important where the adjacent structure is an airplane andthe following structure is a loading ramp.

More particularly, an object of the invention is to provide a controlmeans which includes a supporting member mounted on the followingstructure for pivotal movement from a retracted position toward theadjacent structure into an extended position, the sensing member beingpivotally mounted on the supporting member about an axis perpendicularto the plane of pivotal movement of the supporting member and having anarcuate surface which is frictionally and rollably engageable with theadjacent structure when the supporting member is in its extendedposition. A related object is to provide a sensing member which has theform of a sensing roller the cylindrical surface of which isfrictionally and rollably engageable with the adjacent structure.

Other objects of the invention are to provide means for biasing thesupporting member toward its extended position so as to urge the sensingroller into frictional engagement with the adjacent structure, and toprovide means for inactivating the control means by displacing thesupporting member into its retracted position.

The foregoing objects, advantages, features and re sults of the presentinvention, together with various other objects, advantages, features andresults thereof which will be evident to those skilled in the art towhich the invention relates, may be attained with the exemplaryembodiment of the invention described in detail hereinafter andillustrated in the accompanying drawing, in which:

FIG. 1 is a view, partially in side elevation and partially in section,showing two interengageable and relatively movable structures one ofwhich incorporates the apparatus of the invention;

FIG. 2 is an enlarged view, partially in Section and partially inelevation, illustrating a control means of the invention;

FIG. 3 is an enlarged, fragmentary sectional view taken along thearrowed line 33 of FIG. 2; and

FIG. 4 is a diagrammatic view of the control means of the invention.

Referring initially to FIG. 1 of the drawing illustrated therein is aportion of a telescoping loading and unloading ramp 10 comprising anouter tunnel 12 the outer end of which is engageable with an airplanefuselage .14 around a doorway 16 therein. The tunnel 12 is supported bya self-propelled, steerable, vertically extensible and contractibletruck 18 by means of which the outer end of such tunnel may bemaneuvered into register with the doorway 16. The truck 13 includes atelescoping column 20 which may be extended and contracted to raise andlower the tunnel 12 by a reversible motor means 22 shown as comprising areversible electric motor 24 carried by the tunnel and driving a screw26 within the telescoping column. For a more detailed description of theforegoing structure, attention is directed to the copending patentapplication of Robert D. Lichti, one of the inventors hereof, Serial No.38,843, filed June 27, 1960, now abandoned the disclosure of which isincorporated herein by reference. However, it will be understood thatvarious reversible motor means may be utilized for raising and loweringthe tunnel 12, the reversible electric motor 24 and the screw 26 shownbeing illustrative only.

In order to maintain the tunnel 12 in register with the doorway 16, andin order to prevent damage to the fuselage 14 and/ or the ramp 10, it isessential that the outer end of the tunnel and the portion of thefuselage engaged thereby be maintained at the same relative levels atall times, despite the presence of factors tending to produce relativevertical movement of the tunnel and the fuselage. The elevation of thedoorway 16 may vary throughout a considerable range as passengers enteror leave, as baggage is loaded or unloaded, as the fuel tanks of theairplane are filled, and the like, and the tunnel 12 must follow theresulting vertical movement of the portion of the fuselage 14 around thedoorway very closely. To a lesser degree, the tunnel 12 itself may tendto move vertically relative to the fuselage 14, e.g., as passengersenter and leave the tunnel, and any such tendency of the tunnel to movevertically relative to the fuselage must be prevented.

The present invention provides a control means, designated generally bythe numeral 30, which operates the reversible motor means 22 indirections to maintain the tunnel 12 and the fuselage 14 in the samerelative vertical positions in response to very slight relative verticalmovements thereof. In the construction illustrated, the control means 30is carried by the tunnel 12 and is engageable with the fuselage 14.

Referring particularly to FIG. 2 of the drawing, the control means 30includes a supporting member or control arm 32 which is pivotallymounted intermediate its ends, at 34, on the tunnel 12 for movementtoward and away from the fuselage 14 between extended and retractedpositions. The extended position of the control arm 32 is shown in solidlines in FIG. 2 of the drawing and the retracted position thereof isshown in broken lines. A tension spring 36 connected at one end to thecontrol arm 32 and at its other end to the tunnel 12 biases the controlarm toward its extended position.

Pivotally mounted on one end of the control arm 32 is arelative-vertical-movement-sensing roller 38 having thereon a tire-likecollar 40, preferably of an elastomeric material, which is engageablewith the fuselage 14 adjacent the doorway 16 therein when the controlarm is in its extended position. The ivot axis of the sensing roller 38is perpendicular to the plane of pivotal movement of the control arm 32so that the circumferential collar 40 on the sensing roller isfrictionally and rollably engageable with the fuselage 14. In otherwords, if any slight relative vertical movement of the tunnel l2 and thefuselage 14 occurs, the sensing roller 38 rolls upwardly or downwardlyalong the fuselage. With this construction, any possibility of damage toor marring of the external surface of the fuselage 14 is prevented sincethe sensing roller 38 merely rolls vertically over the external surfaceof the fuselage, and does not slide relative thereto. Also, since thecontrol arm 32 is free to pivot in opposition to the action of thebiasing spring 36, the possibility of damage to the fuselage 14 isfurther minimized.

As shown in FIG. 3 of the drawing, tire sensing roller 38 is fixed on ashaft 42. oriented perpendicular to the plane of pivotal movement of thecontrol arm 32. The shaft 4-2 is rotatable relative to the conrtol arm32 and is connected at its inner end to a control switch designatedgenerally by the numeral The control switch may be of any suitableconstruction, but is basically a double throw switch capable ofenergizing the reversible electric motor 24 in opposite directions. Asshown diagrammatically in FIG. 4 of the drawing, the control switch 44basically includes a switch element 46 adapted to close either a Downcircuit 48, or an Up circuit 59. It will be understood that thereversible electric motor 24 is connected in the circuits d8 and 50 insuch a manner that it lowers the tunnel 12 when the Down circuit 3 isclosed and raises the tunnel when the Up circuit St) is closed.

In operation, if the fuselage 14 starts to move downwardly relative tothe tunnel 12, of if the tunnel starts to move upwardly relative to thefuselage, the sensing roller 38 is rotated in the clockwise direction,as viewed in the drawing, to close the Down circuit 4 3. Consequently,the motor means 22 lowers the tunnel 12 to fol low the fuselage 14downwardly, or to prevent the tunnel from rising relative to thefuselage, as the case may be. The operation of the control means 36 issimilar, but reversed in direction, whenever the fuselage 14 starts tomove upwardly relative to the tunnel 12, or whenever the tunnel 12starts to move downwardly relative to the fuselage 14.

Only a few degrees of rotation of the sensing roller 38 from its neutralposition are necessary to effect closure of one or the other of thecircuits 48 and t Consequently, only a very slight relative verticalmovement of the tunnel 12. and the fuselage 14 is necessary to actuatethe reversible motor means 22, thereby reducing the possibility ofdamage to the airplane, or to the ramp lit, to an absolute minimum.

In order to prevent the control means 36 from interfering withmaneuvering of the outer end of the tunnel 12 into the proper positionrelative to the doorway 16, and in order to prevent damage to thecontrol means itself and damage to the airplane by the control meansduring such maneuvering, the control arm 32 is preferably locked in itsretracted position. This may be accomplished in various ways. In theparticular construction illustrated in FIG. 2 of the drawing, thecontrol arm 32 is pivotally connected to one end of a link 52 the otherend of which is pivotally connected to a crank 54. The latter isconnected, as by a cable 56, to a retracting crank 58 which ispreferably mounted at a control station within the tunnel 12. As will beapparent, by pivoting the crank 58 from its solid-line position to itsbrokenline position, the control arm 32 may be pivoted from its extendedposition into its retracted position. The retracting crank 53 may beprovided with any suitable latch means, not shown, for locking thecontrol arm 32 in its retracted position.

Although an exemplary embodiment of the invention has been disclosedherein for purposes of illustration, it

4- will be understood that various changes, modifications andsubstitutions may be incorporated in such embodimcnt without departingfrom the spirit of the invention as defined by the following claims.

We claim:

1. In combination: two relatively movable structures; means includingreversible motor means for relatively moving said structures; andcontrol means responsive to relative movement of said structures foroperating said reversible motor means in directions to maintain saidstructures in the same relative positions, including a supporting membermounted on one of said structures for movement toward and away from theother of said structures, means interconnecting said supporting memberand said one structure for biasing said supporting member toward saidother structure, a sensing member pivotally mounted on said supportingmember and having an areaate surface frictionally and rollablyengageable with said other structure, and a control member directlyconnected to said sensing member, so as to pivot therewith, andoperatively connected to said reversible motor means.

2. In combination: a structure movable in opposite directions in apredetermined plane; means including reversible motor means connected tosaid structure for moving same in said opposite directions in saidplane; a supporting member mounted on said structure for movement insaid plane between retracted and extended positions; meansinterconnecting said structure and said supporting member for biasingsaid supporting member toward said extended position; a sensing memberpivotally mounted on said supporting member for pivotal movementrelative thereto about a pivot axis perpendicular to said plane, saidsensing member having an arcuate surface the center of which is definedby said pivot axis and which is frictionally and rollably engageablewith an adjacent structure when said supporting member is in saidextended position; and a control member directly connected to saidsensing member, so as to pivot therewith, and operatively connected tosaid reversible motor means.

3. In combination: a structure movable in opposite directions in apredetermined plane; means including reversible motor means connected tosaid structure for moving same in said opposite directions in saidplane; a supporting member mounted on said structure for pivotalmovement in said plane between retracted and extended positions; meansinterconnecting said structure and said supporting member for biasingsaid supporting member toward said extended position; a sensing memberpivotally mounted on said supporting member for pivotal movementrelative thereto about a pivot axis perpendicular to said plane, saidsensing member having an arcuate surface the center of which is definedby said pivot axis and which is frictionally and rollably engageablewith an adjacent structure when said supporting member is in saidextended position; and a control member directly connected to saidsensing member, so as to pivot therewith, and operatively connected tosaid reversible motor means.

4. In combination: a structure movable in opposite directions in apredetermined plane; means including reversible motor means connected tosaid structure for moving same in said opposite directions in saidplane; a supporting member mounted on said structure for pivotalmovement in said plane between retracted and extended positions; meansinterconnecting said structure and said supporting member for biasingsaid supporting member toward said extended position; a sensing rollerpivotally mounted on said supporting member for pivotal movementrelative thereto about a pivot axis perpendicular to said plane, saidsensing roller having an arcuate surface the center of which is definedby said pivot axis and which is frictionally and rollably engageablewith an adjacent structure when said supporting member is in saidextended position; and a control member directly connected to saidsensing roller, so as to pivot therewith, and operatively connected tosaid reversible motor means.

5 6 5. The combination set forth in claim 4 wherein said 1,797,808Tomkinson Mar. 24, 1931 reversible motor means is a reversible electricmotor and 2,015,967 Ryder Oct. 1, 1935 wherein said control member is adouble throw switch- 2,2i95,519 Millikin Sept. 8, 1942 2,594,716 BaileyApr. 29, 1952 References Cited 1n the file of this patent 5 2,617,587Carpenter NOV. 11 1952 UNITED STATES PATENTS 2,622,816 Koch Dec. 23,1952 1 5 9, 73 wi June 22, 1926 2,674,343 Santini P 5, 1954 1,658,577Smoot Feb. 7, 1928 2,922,345 Memes 26, 1960

1. IN COMBINATION: TWO RELATIVELY MOVABLE STRUCTURES; MEANS INCLUDINGREVERSIBLE MOTOR MEANS FOR RELATIVELY MOVING SAID STRUCTURES; ANDCONTROL MEANS RESPONSIVE TO RELATIVE MOVEMENT OF SAID STRUCTURES FOROPERATING SAID REVERSIBLE MOTOR MEANS IN DIRECTIONS TO MAINTAIN SAIDSTRUCTURES IN THE SAME RELATIVE POSITIONS, INCLUDING A SUPPORTING MEMBERMOUNTED ON ONE OF SAID STRUCTURES FOR MOVEMENT TOWARD AND AWAY FROM THEOTHER OF SAID STRUCTURES, MEANS INTERCONNECTING SAID SUPPORTING MEMBERAND SAID ONE STRUCTURE FOR BIASING SAID SUPPORTING MEMBER TOWARD SAIDOTHER STRUCTURE, A SENSING MEMBER PIVOTALLY MOUNTED ON SAID SUPPORTINGMEMBER AND HAVING AN ARCUATE SURFACE FRICTIONALLY AND ROLLABLYENGAGEABLE WITH SAID OTHER STRUCTURE, AND A CONTROL MEMBER DIRECTLYCONNECTED TO SAID SENSING MEMBER, SO AS TO PIVOT THEREWITH, ANDOPERATIVELY CONNECTED TO SAID REVERSIBLE MOTOR MEANS.